JPH05201125A - Pressure-sensitive recording sheet - Google Patents

Abstract

PURPOSE:To obtain a pressure-sensitive recording sheet on a bar of which a blur by overlap aging is not generated after printing of the bar code, by a method wherein a microcapsule layer provided on sheets of paper each is made to contain specific capsule oil. CONSTITUTION:At the time of combining of top sheet of paper, middle sheet of paper and bottom sheet of paper with one another, though a microcapsule layer provided on the sheets of paper each is made to contain capsule oil, at least 40wt.% capsule oil and preferably not exceeding 80wt.% paraffin solvent having the boiling point of not exceeding 200 deg.C is preferable. With this construction, since solubility of a color former is controlled, color development more than it is required is eliminate and furthermore the paraffin solvent is apt to evaporate, it becomes possible to prevent a blur of a bar code by overlap aging after bar code printing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensitive recording sheet, and more particularly to a bar code reading pressure sensitive recording sheet.

[0002]

2. Description of the Related Art Conventionally, a pressure-sensitive copying paper which is generally used has a form as follows. That is, an "upper paper" having a coating layer of microcapsules containing micro oil droplets in which an electron-donating organic color former is dissolved or dispersed is provided on one side of the substrate, and an electron-accepting colorant coating layer. There are "lower leaf paper" that has one side of the supporting base, "medium leaf paper" that has a coating layer of microcapsules on one side of the base body, and a coating layer of a coloring agent on the other side of the base body. When paper, middle-leaf paper, and lower-leaf paper are actually used, the upper-leaf paper and the lower-leaf paper are stacked so that their respective coating surfaces face each other, or when it is desired to obtain a large number of copies, the upper-leaf paper is used. Insert one or more sheets of middle leaf between the paper and the lower leaf. When a type or writing pressure is applied to the pressure-sensitive copy papers that are overlapped in this way to form a set, the microcapsules in the pressurizing section are destroyed and the color former inside is transferred to the colorant layer together with the oil to react.
A color image is obtained.

In recent years, bar codes have been used in various fields, and also in the field of pressure-sensitive recording sheets, bar codes are printed and utilized. The pressure-sensitive recording sheet composed of a combination of the upper leaf paper, the middle leaf paper and the lower leaf paper as described above is capable of simultaneously recording on a plurality of sheets, and is very important as a document requiring simultaneous recording. ing.

However, if a bar code is printed on such a known pressure-sensitive recording sheet and after printing, the upper leaf paper, the middle leaf paper, and the lower leaf paper are piled up, the middle leaf just below the upper leaf paper. There is a problem that the barcode (color development image) on the paper or the lower sheet causes blurring or color erasing, making it impossible to read the barcode.

[0005]

Therefore, as a result of various investigations by the present inventors to solve these problems, the microcapsule layer provided on each leaf paper at the time of bar code printing on the pressure-sensitive recording sheet. It was found that the color-forming agent contained in the above developed color more than necessary and caused bleeding on the barcode of the middle-leaf paper or the lower-leaf paper.

Accordingly, it is an object of the present invention to provide a pressure-sensitive recording sheet which does not cause the bleeding of the barcode due to the passage of time after printing the barcode.

[0007]

The above objects have been achieved by the present invention described below. That is, in a pressure-sensitive recording sheet composed of a combination of upper leaf paper, middle leaf paper and lower leaf paper, 40% by weight or more of the capsule oil contained in the microcapsule layer provided on each leaf paper is a paraffinic solvent. This is a pressure-sensitive recording sheet.

As described above, according to the present invention, since the paraffinic solvent is used in an amount of 40% by weight or more of the capsule oil, the solubility of the color former is suppressed and unnecessary color development is eliminated.
Further, since the paraffinic solvent is easily evaporated, it is possible to prevent the bleeding of the bar code due to the passage of time after printing the bar code. On the other hand, when the amount of the paraffinic solvent is less than 40% by weight, the bleeding of the bar code occurs due to the lapse of time after the bar code is printed and the bar code becomes unreadable.

The paraffinic solvent of the present invention is preferably 8
It is 0% by weight or less. In a conventional recording sheet, a paraffinic solvent is used as a diluent, and the amount used is 30% by weight or less. As described above, since the color former is difficult to dissolve in the paraffinic solvent, it has been used only as an auxiliary agent. However, as a result of various investigations by the inventors, it has been possible to provide a pressure-sensitive recording sheet capable of preventing the bleeding of the bar code after the bar code is printed, paying attention to the fact that the color former is hardly dissolved in the paraffinic solvent. Is.

Further, in the present invention, the boiling point of the paraffinic solvent (fraction 50%) is preferably 200 ° C. or lower.
Further, the pressure-sensitive recording sheet of the present invention is preferably for reading barcodes. The present invention will be described in detail.

Examples of the paraffinic solvent used in the present invention are as follows.

[0012]

[Table 1] Table 1 ─────────────────────────────────── Trade name Manufacturer Boiling point (℃) (min 50%) ─────────────────────────────────── IP Solvent 1016 Idemitsu Petrochemical 113 IP Solvent 1620 〃 178 ISOPAR L Esso Standard Oil 192 Shell Sol 71 Shell Chemistry No. 1820 Solvent L Nippon Oil 194 Nisseki Isosol 200 〃 111 Nisseki Isosol 300 〃 181 ────────────────── ─────────────────

In the present invention, as the electron-donating dye (color former), colorless or light-colored triallylmethane type dyes, diphenylmethane type dyes, spiro type dyes, fluorane type dyes and the like which are conventionally used in pressure-sensitive recording sheets are used. It is used, but in order to obtain an image with a high reading rate especially with a barcode reader, the absorption maximum of a color image obtained by a reaction with an electron-accepting developer as an electron-donating dye is 620 to 620.
It is preferable to use a phthalide compound, an azaphthalide compound, a diazaphthalide compound and a fluorane compound having a wavelength of 720 nm.

Specific examples of these compounds are shown in Tables A, B and C.

[0015]

[Chemical 1]

[0016]

[Table 2]

[0017]

[Chemical 2]

[0018]

[Table 3]

[0019]

[Chemical 3]

[0020]

[Chemical 4]

[0021]

[Table 4]

[0022]

[Table 5]

The color former used in the present invention is dissolved in a solvent, encapsulated and applied to a support. As the solvent, besides the paraffinic solvent used in the present invention, a natural or synthetic oil may be used in combination for the purpose of dissolving the color former. Examples of the solvent include cottonseed oil, soybean oil, vegetable oil such as olive oil, naphthene oil, alkylated biphenyl, alkylated terphenyl, chlorinated paraffin, alkylated naphthalene, diarylalkane, phthalic acid ester and the like.

As the method for producing the color-forming agent-containing microcapsules, an interfacial polymerization method, an internal polymerization method, a phase separation method, an external polymerization method, a coacervation method and the like are used. A water-soluble binder or a latex binder is generally used for preparing a coating liquid containing a color-forming agent-containing microcapsule. Further, a capsule protecting agent such as cellulose powder, starch particles, talc, etc. is added to obtain a color developer-containing microcapsule coating solution.

Examples of developers that react with the color former used in the pressure-sensitive recording sheet of the present invention include acidic clay, activated clay, attapulgite, zeolite, bentonite, clay substances such as kaolin, and metals of aromatic carboxylic acid. Examples thereof include salts and phenol formaldehyde resins.

[0026]

【Example】

Example I-1 [Preparation of Microcapsule Liquid Containing Coloring Agent] Specific example (A-1) of the compound shown in Table A as a coloring agent (A-1) 3.6 g and specific example (C-1) of the compound shown in Table C 2.0g and 2-
4.0 g of anilino-3-methyl-6-N-ethyl-N-isoamylaminofluorane are dissolved in 60 g of diisopropylnaphthalene. IP Solvent 1620 (manufactured by Idemitsu Petrochemical Co., Ltd.) as a paraffin solvent is added to this oily liquid.
g, 10 g of carbodiimide-modified diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Company, trade name “Millionate MTL”) as a polyvalent isocyanate and hexamethylene diisocyanate pyruette (manufactured by Sumitomo Bayer Urethane Co., trade name “Sumijour N320”).
0 ") and 5 g of ethylene oxide as a alkylene oxide adduct of ethylenediamine (3.0 g of butylene oxide adduct of ethylenediamine (molar number of addition of butylene oxide to ethylenediamine: 16.8 mol, molecular weight: 1267)) were dissolved to prepare a primary solution.

Next, 1 part of polyvinyl alcohol was added to 140 g of water.
A secondary solution was prepared by dissolving 0 g and 5 g of carboxymethyl cellulose. The second solution was vigorously stirred and the above 1
The next solution was poured to form an oil-in-water emulsion. When the size of the oil droplet reached 5.0μ, weaken the stirring and then add 100 mL of water at 20 ° C to this emulsion.
After the addition of g, the system temperature was gradually raised to 70 ° C. and kept at this temperature for 90 minutes.

To the thus obtained capsule liquid, 80 g of a 15% aqueous solution of polyvinyl alcohol, 30 g of carboxy-modified SBR latex in solid content, and 60 g of starch particles (average particle size 15 μ) were added. Next, water was added to adjust the solid content concentration to 20% to prepare a color-forming agent-containing microcapsule liquid. [Preparation of color developer dispersion] 100 g of 3,5-bis (α-methylbenzyl) salicylate zinc was added to 80 g of xylene and dissolved.

This xylene solution was added to 120 g of a 4% polyvinyl alcohol (PVA-205 manufactured by Kuraray) aqueous solution, 4 g of a 10% polyoxyethylene sorbitan oleate aqueous solution was further added as a surfactant, and the emulsion was averaged with a homogenizer. An emulsified dispersion was prepared so that the particle size was 1.0 μm. Next, 180 g of water was added to this emulsified dispersion and then heated to remove azeotropically xylene and water from the emulsified dispersion to adjust the solid content concentration to 30% to obtain a developer dispersion. It was [Preparation of developer coating liquid] Calcium carbonate 120 g, zinc oxide 20 g, sodium hexametaphosphate 1 g and water 20
Using 0 g, an inorganic pigment dispersion liquid obtained by atomizing with a sand mill was obtained.

9% PVA was added to 300 g of this inorganic pigment dispersion.
-117 (manufactured by Kuraray) and 200 g of carboxy-modified SBR latex (manufactured by Sumitomo Nogatac, SN30)
7) 4 g (as solid content) was added, and further 15 g of the above-mentioned developer dispersion was added and hydrolyzed to a solid content concentration of 20% to obtain a developer coating solution. The [middle lobe paper coating] the color former containing microcapsules solution on one surface of the base paper 40 g / m ^2, so that the solid content of 4.0 g / m ² is applied, the color developer coating on the other surface The liquid was applied by an air knife coater so that a solid content of 4.5 g / m ² was applied and dried to obtain a mid-leaf paper. Example I-2 IP Solvent 1620 (manufactured by Idemitsu Petrochemical) 60 in [Preparation of microcapsule solution containing color former] of Example I-1
Nisseki Isozol 300 (Nippon Petroleum) 6 instead of g 6
A mid-leaf paper was obtained in the same manner as in Example I-1, except that 0 g was used. Example I-3 IP Solvent 1620 (manufactured by Idemitsu Petrochemical Co., Ltd.) 60 in [Preparation of Microcapsule Liquid Containing Coloring Agent] of Example I-1
Nisseki Isozol 200 (Nippon Petroleum) 6 instead of g 6
A mid-leaf paper was obtained in the same manner as in Example I-1, except that 0 g was used. Comparative Example I-1 IP Solvent 1620 (manufactured by Idemitsu Petrochemical Co., Ltd.) 60 in [Preparation of Microcapsule Liquid Containing Coloring Agent] of Example I-1
A mid-leaf paper was obtained in the same manner as in Example I-1 except that 40 g of diisopropylnaphthalene and 20 g of IP Solvent 1620 (manufactured by Idemitsu Petrochemical) were used instead of g. Comparative Example I-2 IP Solvent 1620 (manufactured by Idemitsu Petrochemical Co., Ltd.) 60 in [Preparation of Coloring Agent-Containing Microcapsule Liquid] of Example I-1
A mid-leaf paper was obtained in the same manner as in Example I-1, except that 60 g of diisopropylnaphthalene was used instead of g. Example II-1 [Preparation of Microcapsule Liquid Containing Coloring Agent] Specific example of compound (B-2) shown in Table B as a coloring agent (B-2) 2.0 g and compound (C-2) shown in Table C 1.0g and 2-
4.0 g of anilino-3-methyl-6-dibutylaminofluorane are dissolved in 50 g of 1-phenyl 1-xylylethane. Into this oily liquid, 70 g of IP Solvent 1016 (made by Idemitsu Petrochemical) as a paraffinic solvent, 8 g of polymethylene polyphenyl polyisocyanate (manufactured by Nippon Polyurethane Co., trade name "Millionate MR200") as a polyvalent isocyanate, and hexauret of hexamethylene diisocyanate A primary solution was prepared by dissolving 8 g of a body (trade name "Sumijour N3200" manufactured by Sumitomo Bayer Urethane Co., Ltd.).

Next, 1 part of polyvinyl alcohol was added to 140 g of water.
A secondary solution was prepared by dissolving 0 g and 5 g of carboxymethyl cellulose. 1 above while vigorously stirring the secondary solution
The next solution was poured to form an oil-in-water emulsion. When the size of the oil droplet reached 8.0μ, the stirring was weakened, and then 100 mL of water at 20 ° C was added to this emulsion.
After adding g and 1.6 g of diethylenetriamine, the temperature of the system was gradually raised to 90 ° C. and kept at this temperature for 60 minutes. 80 g of a 15% aqueous solution of polyvinyl alcohol and carboxy-modified SB were added to the capsule liquid thus obtained.
15 g of R latex in solid content and 30 g of starch particles (average particle size 15 μ) were added.

Then, water is added to adjust the solid content concentration to 20%.
Was adjusted to prepare a color developer-containing microcapsule solution. [Application of Mid-Sheet Paper] The microcapsule solution containing the color former was applied to one side of 40 g / m ² base paper so that the solid content of 4.5 g / m ² was applied to the other side of Example I-1. The developer coating solution was applied and dried with an air knife coater so that a solid content of 4.5 g / m ² was applied, to obtain a mid-leaf paper. Example II-2 IP Solvent 1016 (manufactured by Idemitsu Petrochemical) 70 in [Preparation of Coloring Agent-Containing Microcapsule Liquid] of Example II-1
A mid-leaf paper was obtained in the same manner as in Example I-1, except that 70 g of IP Solvent 1620 (manufactured by Idemitsu Petrochemical Co., Ltd.) was used instead of g. Example II-3 IP Solvent 1016 (manufactured by Idemitsu Petrochemical Co., Ltd.) 70 in [Preparation of Microcapsule Liquid Containing Coloring Agent] of Example II-1
A mid-leaf paper was obtained in the same manner as in Example II-1 except that 70 g of ISOPAR L (manufactured by Esso Standard Petroleum) was used instead of g. Comparative Example II-1 IP Solvent 1016 (manufactured by Idemitsu Petrochemical) 70 in Preparation of Microcapsule Solution Containing Coloring Agent of Example II-1
45 g of 1-phenyl-1-xylylethane instead of g
A mesoleaf paper was obtained in the same manner as in Example II-1 except that 25 g of IP Solvent 1016 (manufactured by Idemitsu Petrochemical) was used. Comparative Example II-2 IP Solvent 1016 (manufactured by Idemitsu Petrochemical) 70 in Preparation of Microcapsule Solution Containing Coloring Agent of Example II-1
70 g of 1-phenyl-1-xylylethane instead of g
A mid-leaf paper was obtained in the same manner as in Example II-1 except that was used.

The above-mentioned mid-leaf paper was evaluated as a bar code reading pressure-sensitive recording sheet, and the results are shown in Table I. The evaluation test was performed by the following method. (1) Bar code printing Four sheets of each medium-sized paper are overlaid and printed with a dot impact printer (Oki Electric Co., Ltd., MICROLINE 8340SV) by COD
The number 8 digit of E39 was printed. (2) Bar code reading The print sample obtained in (1) was printed 10 minutes after printing, and after printing, four sheets of middle paper were overlaid and a load of 50 g / cm ² was applied to the room (23 ° C, RH 65%) for 2 weeks. 2 after leaving
A bar code reader (Nippon Denso Co., Ltd., BHT-2061) was used to read and test the first bar code. (3) Evaluation of bleeding of bar code print The bleeding of the second bar code print after being left indoors in (2) was visually evaluated.

[0034]

[Table 6]

As shown in Table 1, the pressure-sensitive recording sheet of the present invention can be read without causing the bleeding of the bar code due to the passage of time after printing the bar code.

[0036]

EFFECTS OF THE INVENTION It is possible to provide a pressure-sensitive recording sheet that does not cause bleeding or decoloration of a colored image by bar code printing.

Claims (3)

[Claims] 1. A pressure-sensitive recording sheet comprising a combination of an upper leaf paper, a middle leaf paper and a lower leaf paper, and 4 capsule oils contained in a microcapsule layer provided on each of the leaf papers.
A pressure-sensitive recording sheet, characterized in that 0% by weight or more is a paraffinic solvent. 2. Boiling point of paraffinic solvent (fractionation 50%)
Is 200 ° C. or less, the pressure-sensitive recording sheet according to claim 1. 3. The pressure-sensitive recording sheet according to claim 1, wherein the pressure-sensitive recording sheet is for reading a barcode.